Sewing machine shuttle



Nov. 9, 1937, D 2,098,269

SEWING MACHINE SHUTTLE Filed Jan. 2, 1957 Alfred R Wood Patented Nov. 9,1937 SEWING MACHINE SHUTTLE Alfred E. Wood, Bridgeport, Conn, assignorto The Singer Manufacturing Company, Elizabeth, N. J., a corporation ofNew Jersey Application January 2', 1937, Serial No. 118,845

2 Claims.

This invention relates to sewing machine shut-' tles, more particularlyof the type comprising a circularly moving shuttle-body having an arboron which a stationary cup-shaped bobbin-threadcase is journaled. Ametallic bobbin wound with thread is customarily received within thethreadcase, which latter commonly has a tubular central memberconstituting a bearing for the thread-case upon the arbor of theshuttle-body and further constituting an arbor for the bobbin.

Thread manufacturers furnish sewing machine users with Wound cops ofthread on paper spools of approximately the same size and shape as themetallic bobbin in lieu of which they are designed to be used. Thesefactory wound cops, however, have a tendency to swell or shrink,depending upon atmospheric conditions, and hence must be manufacturedwithin such size limits that under no condition will they bind or dragin the sewing 0 machine thread-case but will under all conditions befree to unwind within the thread-case. As a result of this requirement,the wound paper spool or cop usually fits the thread-case more freely orwith more play than the metallic bobbin, but in neither case is itpracticable to fit the rims of the bobbin flanges so closely within theinner cylindrical wall of the thread-case that the bobbin-thread cannotat times escape therebetween.

When a lock-stitch sewing machine is operated at high speeds, thebobbin-thread is subjected to a rapid succession of jerks whichfrequently causes the bobbin to overrun and spill the bobbin-threadwithin the thread-case. When bobbin-thread is spilled within thethread-case it frequently escapes or leaks out of the threadcase and isfouled, caught, kinked or broken by parts of the machine. Muchexperimenting has been done and many devices have been made to preventspilling of bobbin-thread within the thread-case and subsequent leakageof spilled thread therefrom. Such devices commonly comprise some sort ofspring washer or friction means to be housed with the bobbin or copwithin the bobbin-case for the purpose of placing a frictional drag uponsuch bobbin or cop. These de vices have not been successful for variousreasons, chiefly because they impose a variable tension upon thebobbin-thread depending upon the amount of thread on the bobbin. Thetension caused by this drag is least with a full bobbin and increases asthe bobbin unwinds, becoming a maximum when the bobbin is practicallyexhausted. Uniform sewing cannot be done under such conditions.

The present invention aims to provide an improved sewing machine shuttlefrom which the bobbin-thread cannot escape under any condition and withwhich uniformly satisfactory sewing may be done using either woundmetallic bobbins or paper clad cops.

With the above and other objects in View, as will hereinafter appear,the invention comprises the devices, combinations, and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingof a preferred embodiment of the invention, from which the severalfeatures of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

According to the present improvement no attempt is made to preventspilling of bobbinthread within the thread-case, but means are providedto effectively prevent escape of the spilled thread from thethread-case.

The invention will be more fully understood by reference to theaccompanying drawing, of which Fig. l is a front face elevation of asewing machine shuttle embodying the invention. Fig. 2 is a rear faceview of the shuttle. Fig. 3 is an enlarged section on the line 33,Fig. 1. Fig. 4 is a perspective View of the shuttle body from which thethread-case has been removed. Fig. 5 is a disassembled perspective viewof the thread-case and cop, and Fig. 6 is a fragmentary sectional viewsimilar to Fig. 3 but on a still further enlarged scale.

The shuttle body A of the circularly moving oscillatory type is formedas usual with a semicircular bearing rib l terminating at one end in aloop-taking beak 2. The shuttle body A is further formed with a rearwall 3 which supports the arbor 4 on which the stationary cup-shapedthreadcase B is journaled.

The cup-shaped thread-case B has at its open end a circular rim 5 and aninternal tubular bearing element 6 coaxial with the rim 5 and freelyjournaled on the arbor 4. The thread-case is adapted to receive theusual bobbin-thread spool or cop l which must be of a size such that itwill not drag appreciably upon the thread-case or its bearing element 6as the bobbin-thread 8 is being used.

The bobbin-thread 8 is drawn through the threading slot 9 and under theusual tensionspring ID from which it leads upwardly through the guidehole H in the rotation-restraining arm l2 to the work. In practice, therotation-restraining arm l2 on the thread-case B is loosely engaged atits upper end by a notched rotation-restraining element (not shown)fixed on the sewing machine frame.

The thread-case B has the usual spring-pressed latch slide l3 whichengages the shoulder 14 in 5 the arbor 4. The latch slide l3 has hingedto it at l5 a finger-operated lever l6 formed at one end with a shortarm 16' which, when the lever [B is swung about the hinge I5 bears uponthe fixed corner I! of the thread-case and effects re- 10 traction ofthe latch-slide from engagement with the shoulder l4, thus unlocking thethread-case for removal from the arbor 4. The finger-operated lever 18has an upturned free terminal portion l6 by which it is readily engagedand opened by the operator. The broadly curvedfree edge 16 at theterminal portion of the lever 16 permits the free and easy passage ofthe cast needle-loop thereover as the needle loop is being drawn up inthe usual manner by the sewing machine take-up (not shown). 7 g

' The shuttle-body A is formed in the inner face of its rear wall 3 witha completely circular groove l8 the diameter a of which is approximatelyequal to that of the rim 5 of the thread-case in juxtaposition thereto.Preferably, the rim 5 is smoothly rounded in cross-section and receivedin the groove l8; being clear of the walls of the latter. Thisconstruction provides a tortuous or bent clearance gap, Fig. 6, betweenthe groove 18 '30 and rim 5 which forms an eifective seal against escapeor leakage of spilled bobbin-thread, without subjecting the parts tofrictional wear or requiring extreme accuracy in their manufacture. Anythread spilled within the thread-case will be used up in regular coursewithout danger of being fouled, caught or broken by moving parts outsideof the thread-case, or of being wedged between the thread-case andshuttle-body and damaged in consequence thereof.

Having thus set forth the nature of the invention, what I claim hereinis:

1. In a sewing machine, the combination with a stationary cup-shapedbobbin-case having at its open end a circular rim and having within it atubular bearing element coaxial with said rim, of a circularly movingshuttle-body having an arbor on which said bearing element is freelyjournaled and a rear wall which carries said arbor and is formed in itsinner face with a completely circular groove of substantially the samediameter as-the rim of the thread-case and in juxtaposition with saidrim.

2. In a sewing machine, the combination with a stationary cup-shapedbobbin-case having at its open end a circular rim and having within it atubular bearing element coaxial with said rim, of a circularly movingshuttle-body having an arbor on which said bearing element is freelyjournaled and a rear wall which substantially closes the open end ofsaid bobbin-case, there being a tortuous clearance gap between said rearwall and the rim of said bobbin-case.

ALFRED R. WOOD.

